This invention relates to the preparation of 1,3-propanediol. In one embodiment, the invention relates to a selective process for manufacturing 1,3-propanediol from ethylene oxide in which production of aldehyde intermediates is relatively low.
1,3-Propanediol is a starting material in the production of polyesters for fibers and films. It is known to prepare 1,3-propanediol in a two-step process involving (1) the cobalt-catalyzed hydroformylation (reaction with synthesis gas, H.sub.2 /CO) of ethylene oxide to intermediate 3-hydroxypropanal (HPA) and (2) hydrogenation of the HPA to 1,3-propanediol. One disadvantage of this route involves the tendency of the HPA intermediate to react with itself, resulting in the formation of intermediate by-products which do not undergo hydrogenation to the desired 1,3-propanediol product.
An alternate route to 1,3-propanediol from ethylene oxide involves production of intermediate methyl 3-hydroxypropionate followed by hydrogenation of the methyl 3-hydroxypropionate to 1,3-propanediol. This route would have the advantage of eliminating HPA and the associated by-products; however, this route is typically very unselective for 1,3-propanediol because of the tendency of the methyl 3-hydroxypropionate to undergo hydrogenolysis in the presence of ester hydrogenation catalysts such as copper chromium oxide or Raney nickel.
It is therefore an object of the invention to provide a selective, efficient process for hydrogenating methyl 3-hydroxypropionate to 1,3-propanediol. It is a further object of a specific embodiment of the invention to provide a selective process for the preparation of 1,3-propanediol via methyl 3-hydroxypropionate intermediate.